Which external cross-over x-over to consider?


I would like to use an active x-over with balanced and single ended i/outputs between pre and power amps for a sub(Martin L. Depth) and my merlins, crossing over at around 40hz.
I never realized that there are a bunch of extrenal x-overs to choose from. Which ones would be of higher quality?
Here are some I have found, but I am sure there are many more:
Marchand's xm126 & xm-44,
nht's x1 & x2,
Bryston's 10b,
Mark levinson LNC,
deqx pdc-2.6,
Audio Research EC21.
If there are others worthy of looking at let's hear about them.
pedrillo
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The one thing it doesn't have is balanced inputs and outputs. I like how my sims (pre & power amps) sound in balanced mode.
I would enjoin you to consider a second subwoof instead of an external electronic xover. Sonically, there will be little if any perceptible difference between balanced & SE at low frequencies. There will be perceptible & significant difference b/ween one & 2 subwoofs.

Anyway, amongst the units you list, the Marchand is the usual culprit, well made, good sound, & dependable.
I use the Ashly 3.24 CL with great results. I use it with Final Sound 1000i's and two subs.
Dear Pedrillo: I agree with Gregm about bass performance through balanced or unbalanced way.

IMHO I think that if you " insist " on the balanced connection it can/could be better to change the sub, Velodyne is a good alternative and comes with balance connection. Btw, like Gregm posted, two Velodynes can delivery magic on your system.

Regards and enjoy the music.
Raul.